1. Field of the Invention
The present invention relates to a feeder apparatus for feeding a web to a printing station of a rotary press. More specifically, the invention relates to a feeder apparatus which can be installed webs having different widths. Further particularly, the invention relates to a feeder apparatus which automates shifting of a web supporting arm and shifting of pre-drive mechanism corresponding to shifting of the web supporting arm.
2. Description of the Related Art
Conventionally, a feeder apparatus which can be installed webs of different width has typically been employed in a newspaper press, for example. The different width of webs includes a full width (W width) web Pa having a width corresponding to 4 newspaper pages, 3/4 width web Pb having a width corresponding to 3 newspaper pages, 1/2 width web Pc having a width corresponding to 2 newspaper pages and so forth, as shown in FIG. 7. These different width of webs are selectively used depending upon page layout of the newspaper. The feeder apparatus is thus variable of installation position of the web relative to the center L of the apparatus. The construction permitting variation of the installation position of the webs generally comprises a rack provided along a main shaft supported on both of left and right frames, and pinions mounted on a pair of arms and engaging with the rack. By manual operation, the pinions are rotated to shift the arms on the main shaft.
On the other hand, in the newspaper press, an automatic splicing apparatus is typically employed for splicing a plurality of webs in sequence. The automatic splicing apparatus pre-drives the new web to be spliced for acceleration so that the peripheral speed thereof becomes consistent with that of the old web upon splicing the old and new webs.
Accordingly, on the outer peripheral surface of the web to be pre-driven, an adhesive pasting margin for splicing and a non-pasting margin for permitting contact of a driving belt are provided. When the contact position of the web driving belt has to be varied associating with shifting of a pair of web supporting arms along the main shaft, the belt is shifted preliminarily in consideration of the predetermined position adjustment so that the belt will not contact with the adhesive pasting margin but certainly contact with the non-pasting margin.
The shifting means for a pair of web supporting arms and the driving means for the web are operated manually by personnel for positioning and fixing at the desired position.
On the other hand, Japanese Unexamined Utility Model Publication (Kokai) No. 61-18849 discloses a technology for automating shifting of the web supporting arms. Namely, in the disclosed technology, for a pair of web supporting arms opposingly mounted on the main shaft extending between left and right frames, a screw rods of the corresponding number to that of the arms are provided along the main shaft. The screw rods are engaged with half nuts built-in the respective arms. The screw rods are alternately driven by a common rotary drive means. In addition, a position sensor is provided at a predetermined position to detect a marking body which shifts together with the arms to cause a drive termination signal to stop the arms at the predetermined position. Then, the arm is fixed in place by the self-locking effect of the screw.
As set forth above, the shifting means of the web supporting arms and the web drive mechanism are generally adapted to manual operation and thus substantially labor intensive work. For the newspaper printing industry which requires quick process and quick notification, it is one of most important problems to be solved.
The automated shifting means for the web supporting arm as disclosed in the above-identified Japanese Unexamined Utility Model Publication No. 61-18849 significantly improves the conventional apparatus which required manual operation. However, since the proposed apparatus employs a shifting adjusting system, in which two screw rods are provided along the main shaft and alternately driven by the common drive means provided on one of the side frame, the mechanism is relatively complicate and large and cannot perform simultaneous adjustment for both of the left and right arms to cause substantial period and attention. Also, it does not permit switching into the manual operation in the case of failure in the power transmitting portion. Furthermore, although the disclosed system utilizes the self-locking of the screw, it is still possible to cause uncontrolled rotation of the screw rods due to vibration generated during printing operation. Therefore, the prior proposed apparatus lacks reliability and certainty in maintenance of the predetermined position.